Problem: Solve for $x$. Enter the solutions from least to greatest. $4x^2 + 72x + 320 = 0$ $\text{lesser }x = $
Explanation: $\begin{aligned} 4x^2 + 72x + 320 &= 0 \\\\ 4(x^2+18x+80)&=0 \end{aligned}$ Now let's factor the expression in the parentheses. $x^2+18x+80$ can be factored as $(x+8)(x+10)$. $\begin{aligned} 4(x+8)(x+10)&=0 \\\\ x+8=0&\text{ or }x+10=0 \\\\ x=-8&\text{ or }x=-10 \end{aligned}$ In conclusion, $\begin{aligned} \text{lesser }x &= -10 \\\\ \text{greater }x &= -8 \end{aligned}$